Sleeve-Type Blowdown Valve (Throttling, Shutoff and Venting)

Service conditions

A globe valve opens or closes its flow path through linear movement of a disc relative to the seat. Disc travel changes the opening at the seat. Throttling service requires suitable disc geometry and an assessment of flow demand, differential pressure and the pressure loss caused by changes in flow direction.

Drain and vent duty requires attention to downstream pressure, flashing or erosion and receiving piping. Define discharge frequency, solids, operating sequence and internal servicing and select suitable passage and operator arrangements.

Configuration

Select the manual operator or actuator to suit the valve torque or thrust requirements and site operating conditions. Provide access and clearance for manual operation. For frequent cycling or remote operation, assess actuator output, duty cycle and valve-position feedback.

Service conditions

Specify the process-fluid composition and steady-state, startup and shutdown conditions, then evaluate the body, wetted internals and sealing materials together. Solids, deposits and cleaning procedures can affect sealing surfaces and operating mechanisms. Base the maintenance plan on the actual service conditions.